Currently, there is a wireless communication terminal connectable to a plurality of different types of networks, as the wireless communication terminal is provided with a wireless communication function such as cellular communication where a medium-to-long-distance service area is covered by one base station, a wireless LAN (Local Area Network) function with a relatively short-distance service area, and the like.
As a network formed by such a plurality of different types of networks, Third Generation Partnership Project (3GPP) conducts discussion on a wireless communication terminal, as well as its relevant communication technology, that has a function of communicating with various different types of networks such as a wireless LAN, a cellular network (3G network), and a wireless wide area network (WWAN) of WiMAX type. Especially, discussion is conducted on such a heterogeneous network aimed at achieving seamless mobility, supporting a plurality of application services required of high QoS (Quality of Service) such as real-time video, VoIP, and valuable data, and the like.
Moreover, as an example, non-patent document 1 listed below discloses a technique of Radio Resource Management (RRM) in 3GPP. In 3GPP, it is possible to, for example, monitor/manage resources used in a wireless base station. This enables communication that efficiently uses resources to be realized.
Furthermore, patent document 1 listed below discloses a mobile node that constantly monitors network quality by performing measurement based on field intensity and wireless bandwidth, and executes handover control according to a state of network quality.    Patent Document 1: International Patent Application Publication WO 2004/057903    Non-patent Document 1: “3rd Generation Partnership Project: Technical Specification Group Radio Access Network; Terminal conformance specification; Radio transmission and reception (FDD) (Release 6)”, 3GPP TS 34.121 v6.3.0, December 2005
3GPP allows for integrated management of a heterogeneous network. For instance, an administrator of a 3G network further manages a wireless LAN, enabling to offer a service of providing a connection point to a wireless communication terminal using a heterogeneous network that combines the 3G network and the wireless LAN.
For example, as shown in FIG. 7, a Packet Data Gateway (PDG) 210 of a wireless LAN 200 is connected to a Packet Data Network Gateway (PDNGW) 130 of a 3G network 100, where the 3G network 100 has a trust relationship with the wireless LAN 200.
Moreover, the 3G network 100 has an evolved Node B (eNB) 150 (only one node is shown in FIG. 7) that functions as a connection point to a wireless communication terminal (hereafter referred to as a UE) 310, and the wireless LAN 200 has an AP (three APs that are AP_a 230a, AP_b 230b, and AP_c 230c are shown in FIG. 7, hereafter also referred to as an AP 230) that functions as a connection point to the UE 310. The UE 310 has, for example, both a 3G network interface connectable to the eNB 150 of the 3G network and a wireless LAN interface connectable to the AP 230 of the wireless LAN 200.
Note that, a communication area (cell) 160 of the eNB 150 is typically wider than communication areas 240a, 240b, and 240c (hereafter the plurality of communication areas are also collectively referred to as a communication area 240) of the APs 230. Besides, the communication area 160 of the eNB 150 and the communication area 240 of the AP 230 are situated so as to overlap each other.
A wireless resource management entity (hereafter simply referred to as a RRM) 110 present in the 3G network 100 is a communication device (or one functional entity within a device) capable of monitoring/recognizing wireless resources of the eNB 150 and managing the resources so as to achieve appropriate and efficient resource use. When the 3G network 100 connects to the wireless LAN 200 under its control, there are cases where it is desirable that the RRM 110 can manage wireless resources of the AP 230 functioning as a network connection point, as with the eNB 150.
In such a case, for example, through the following operation shown in FIG. 8, each UE 310 measures a wireless communication status relating to an AP 230 to which the UE 310 is connected and reports the measured wireless communication status to the RRM 110, as a result of which the RRM 110 can recognize a wireless resource use status of each AP 230. Here, the RRM 110 does not necessarily select and instruct a specific UE 310. For instance, a UE 310 suitable for wireless communication status measurement is selected by each AP 230, or an instruction is simply made to all instructible UEs 310. Besides, a UE 310 merely operates upon receiving a report instruction, and does not necessarily know that the RRM 110 is a transmitter of the instruction and a destination of the report.
In FIG. 8, the RRM 110 transmits information (quality report instruction information) instructing to report communication quality information (a wireless communication status with the AP 230) (step S1001). This is eventually notified as a quality report instruction to the UE 310 (though only one UE 310 is shown in the drawing, the notification may be made to a plurality of UEs 310). The quality report instruction information includes information instructing to measure the wireless communication status with the AP 230 and report a result of the measurement, and contents (measurement items) to be specifically measured. The quality report instruction information is delivered from the RRM 110 to the UE 310 via the PDNGW 130, the PDG 210, and the AP 230 to which the UE 310 is connected (steps S1003, S1005, and S1007).
The UE 310 performs a measurement process according to the measurement contents included in the quality report instruction information (step S1009), and transmits measurement result information including a result of the measurement to the RRM 110 via the AP 230 (step S1011). The measurement result information is delivered from the UE 310 to the RRM 110 via the AP 230 to which the UE is connected, the PDG 210, and the PDNGW 130 (steps S1013, S1015, and S1017). The RRM 110 can recognize current communication quality of the AP 230 from the measurement result information and perform resource adjustment of the AP 230. Likewise, when the RRM 110 collects wireless resources of the eNB 150, transmission/reception of quality report instruction information and measurement result information is performed via the eNB 150.
However, in the case where the RRM 110 manages wireless resources of the AP 230 according to the operation shown in FIG. 8, several problems arise.
For example, since the wireless communication status of the eNB 150 or the AP 230 varies moment by moment, the RRM 110 needs to collect communication quality information including such a wireless communication status promptly and stably. However, when collecting the communication quality information of the AP 230, the quality report instruction information and the measurement result information are transmitted on the wireless LAN 200 as shown in FIG. 8. The wireless LAN 200 predominantly offers a best-effort service, and so there is a problem that promptly collecting the communication quality information of the AP 230 is difficult (in particular, there is a lack of responsiveness in transmitting the measurement result information).
Meanwhile, it is also possible to notify the quality report instruction information relating to the AP 230, from the eNB 150. However, since the communication area of the eNB 150 covers an extremely wide range as compared with the communication area of the AP 230, notifying quality report instruction information in a wide range from the eNB 150 in order to recognize communication quality information of one particular AP 230 causes a waste of notification resources of the eNB 150. In other words, there is a problem that it is undesirable to use a wide range of notification resources in order to notify information useful only in a narrow range.